A block copolymer containing two immiscible blocks is known as a self-organization material. In self-organization of this block copolymer, a fine periodical structure is formed by causing phase separation into a phase of one block and a phase of the other block. This technique can form a structure finer than that obtained by lithography.
Examples of the periodical structure are a sphere (spherical structure), a cylinder (cylindrical structure), and a lamella (plate-like structure). Of these structures, the lamella structure is suitable for obtaining a line & space (L/S) pattern.